AB0500 THE LEVEL OF PERIPHERAL BLOOD LYMPHOCYTE SUBSETS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS WITH RESPIRATORY TRACT INFECTION AND ITS CLINICAL SIGNIFICANCE
Authors: J. Q. Zhang, S. X. Zhang, J. Qiao, M. T. Qiu, X. Li
Journal: Annals of the Rheumatic Diseases (2022)

Background Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disorder. Infections are a most common cause of morbidity and mortality in this patient population[1] and at least 50% of patients with SLE are suffered with infections during the course of their disease [2]. Lymphocytes and Natural killer (NK) cells play an important role in the occurrence and development of SLE[3]. In this study, peripheral blood lymphocyte subsets were detected in these patients, providing reference for early diagnosis and treatment of SLE patients with respiratory tract infection. Objectives To analyze the detection level and clinical significance of peripheral blood lymphocyte subsets in patients with SLE with respiratory tract infection. Methods A total of 333 SLE patients with no recent infection, 95 SLE patients with respiratory tract infection, and 132 healthy individuals matched in age and sex were enrolled in the second Hospital of Shanxi Medical University from July 2014 to December 2016. The characteristics of lymphocyte subsets in the three groups were compared and receiver operating characteristic (ROC) curves were drawn to analyze the predictive value of lymphocyte subsets in SLE patients with respiratory tract infection. Results The counts of T, B, CD4 + T, CD8 + T, NK, Th1, Th2, Th17 and Tregs in SLE non-infection group and SLE infection group were [(1094.235 ± 574.495) / (702.781 ± 432.152), t= -7.169, P &lt; 0.001], [(208.338 ± 210.448) / (177.55 ± 170.256), t = -1.306, P = 0.192], [(503.382 ± 303.498) / (304.075 ± 215.497), t = -7.168, P &lt; 0.001], [(536.705 ± 344.218) / (358.034 ± 235.234), t = -5.802, P &lt; 0.001], [(113.898 ± 101.48) / (61.768 ± 50.127), t = -6.831, P &lt; 0.001], [(86.268 ± 89.081) / (47.92 ± 54.174), t = -3.367, P = 0.001], [(11.363 ± 9.834) / (6.628 ± 6.434), t = -3.622, P &lt; 0.001], [(9.537 ± 10.12) / (5.346 ± 4.731), t = -3.646, P &lt; 0.001], [(25.736 ± 27.013) / (20.78 ± 28.083), t =-1.037,P=0.301] (Figure 1).The above indexes in SLE infection group were lower than those in SLE non-infection groups. When lymphocyte subsets predict pulmonary infection in SLE, the AUC value of CD4 + count is the highest, and the cut-off is 387/ μ l(Table 1). The sensitivity and specificity of predicting SLE pulmonary infection were 75.8% and 38.6%(Figure 2). Table 1. Predictive value of peripheral blood lymphocyte subsets in SLE complicated with respiratory tract infection Indicator AUC P value Jordan index cut-off Susceptibility Specificity (%) (%) B 0.569 0.040 83.9950 0.183 0.421 0.238 CD4 0.714 &lt;0.001 0.372 387 0.758 0.386 CD8 0.682 &lt;0.001 0.325 405 0.726 0.401 CD4+ T /CD8+ T 0.569 0.041 0.000 0.785 0.537 0.370 NK 0.687 &lt;0.001 0.309 82.5 0.768 0.460 Conclusion The absolute number of these subsets in infected SLE patients is significantly lower than that in uninfected patients, which indicates that the low absolute number of these cells can be used as an indicator of high infection risk in SLE patients. CD4 + T lymphocytes and NK cells in patients with respiratory tract infection are significantly lower, and can play a certain predictive value for SLE respiratory tract infection to a certain extent. References [1]Kedves M, Kosa F, Kunovszki P, Takacs P, Szabo MZ, et al. 2020. Large-scale mortality gap between SLE and control population is associated with increased infection-related mortality in lupus. Rheumatology (Oxford ) 59:3443-51 [2]Wang J, Niu R, Jiang L, Wang Y, Shao X, et al. 2019. The diagnostic values of C-reactive protein and procalcitonin in identifying systemic lupus erythematosus infection and disease activity. Medicine (Baltimore ) 98:e16798 [3]Luo Q, Kong Y, Fu B, Li X, Huang Q, et al. 2021. Increased TIM-3(+)PD-1(+) NK cells are associated with the disease activity and severity of systemic lupus erythematosus. Clin. Exp. Med. Disclosure of Interests None declared